1. Field of the Invention
The present invention generally relates to tools for removing insulation from cable. More particularly, the invention relates to tools for quickly and effectively removing insulation from cable having a noncircular cross section, such as power transmission cable having ice breaking ribs molded along the exterior of the cable.
2. Description of Related Art
Electrical cable is typically constructed with an electrically conductive core and an outer layer of insulation which must be removed from the ends in order to connect the cable for use. Tools for accomplishing this job, particularly tools used in the electrical power generation and transmission industry, are referred to as "cable strippers". Although cable strippers vary in design, the tools most commonly used in this industry are handheld tools having a body with a longitudinal cable receiving opening passing through them. A blade is mounted on the body of the tool and projects into the cable receiving opening sufficiently far to cut the insulation from the cable as the body is rotated relative to the cable.
Examples of this basic type of tool include the tools shown in U.S. Pat. No. 3,398,610 issued on May 15, 1967, U.S. Pat. No. 3,433,106 issued on Mar. 18, 1969, U.S. Pat. No. 3,572,189 issued on Nov. 26, 1968 and U.S. Pat. No. DES 297,910 issued on Oct. 4, 1988.
Although these tools differ in features and construction, they share the characteristic that they are all designed for use only on cables that have a circular cross section. In each of these designs, the rotational axis of the tool and the center of the cable are maintained in alignment by contact between an alignment portion of the tool and the outer surface of the cable. Thus, in order for these tools to operate properly, the outer surface of the cable must be smooth and cylindrical.
Recently, the power generation and transmission industry has begun to use power transmission cable having one or more ribs projecting outward from the outer surface of the insulation. This type of cable is most commonly used in exposed locations, for example when strung between poles or transmission towers. The ribs are designed to help the cable shed ice during icing conditions.
Cable with ice breaking ribs are expected to become more widely used, and cable with other noncircular cross sectional shapes are also being investigated for their ice breaking properties. Also, cable having ribs or other noncircular cross sectional shapes may be used in underground locations for identification purposes.
Cable stripping tools of the type presently in use cannot strip the insulation from cables having ribs or noncircular cross sections because the outer surface of the insulation cannot be used for maintaining the alignment needed by the tool. When a prior art tool is used, the alignment portion of the tool bumps up and over the ribs and the rotational axis of the cable stripper does not remain in alignment with the axis of the cable as it is rotated. This misalignment may simply result in a poor stripping job, making it difficult to remove the insulation completely, or the stripping blade may actually damage the inner conductor.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a cable stripping tool for removing insulation cleanly and effectively from cable having a noncircular cross section.
It is another object of the present invention to provide a cable stripping tool which can strip the insulation from cable having different numbers of ice breaking ribs without damaging the inner conductor.
A further object of the invention is to provide a cable stripping tool which may be easily reconfigured to strip insulation from cable having various different cross sectional shapes.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.